What do three promising young starting pitchers, 34-year-old lefthander Erik Bedard and a struggling bullpen equal for the Astros?

A six-man rotation.

After hinting at the move toward the end of a recent 10-game road trip, Astros manager Bo Porter said pregame Wednesday the club will use six starters for the foreseeable future.

Rookie righthander Jarred Cosart (1-0, 0.96 ERA ) is set to start during a series finale against Boston’s Ryan Dempster (6-8, 4.54) at 7:10 p.m. at Minute Maid Park.

He’ll be followed by Bedard, Brad Peacock, Dallas Keuchel, Brett Oberholtzer and Jordan Lyles, who started Tuesday during a 15-10 loss to the Red Sox.

The club will re-evaluate the decision after a six-game run through.

“We’ll run it and see … You look at the woes we’ve had in the bullpen, I think our six starters give us the best opportunity to win,” Porter said. “With those (starters) having an extra day, it allows us to put one of those guys in the bullpen.”

The Astros have used a five-man rotation all year. But Cosart (23), Oberholtzer (24) and Peacock (25) have been strong during the last week. Lyles (22) has struggled while Keuchel (25) has made two unexpected long-relief appearances, but both have been mainstays this seasons and Lyles was considered a long-term rotation fixture just six weeks ago. Bedard is the Astros’ highest-paid player ($1.1 million) and out of place on a rebuilding team with an active $13 million payroll. He’s been reliable this season, though, posting a 4.29 ERA and serving as one of the few remaining veterans on the team.

The Astros’ 4.91 ERA is the worst in MLB and the club’s relievers (5.23) also rank at the bottom of the league.

Notes

Chris Carter is out of the lineup again. He’s been given two off days to clear his head and focus on his approach at the plate.

Rookie shortstop Jonathan Villar underwent an MRI Wednesday for his sprained left thumb. Results are pending.